How to Break the Ammonia Cycle in a Fish Tank

Breaking the ammonia cycle is an important first step in establishing a fish aquarium. Ammonia is a natural but toxic byproduct created by fish waste and excess food. This compound can build up to deadly levels if left untreated. However, breaking the ammonia cycle can be done naturally in your aquarium by limiting the number of fish and supporting nitrifying bacteria, which convert ammonia into less-harmful compounds.

Things You'll Need

  • Filter or air bubbler
  • Heater
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Instructions

    • 1

      Ensure your aquarium isn't overcrowded. Too many fish in the water will create excessively high waste loads, which will increase the level of ammonia in your tank. Typically, an established aquarium should house one inch of fish per gallon of water.

    • 2

      Don't overfeed the fish. Unconsumed food will break down into nitrogen compounds, which will increase the amount of ammonia in the aquarium. Make sure the fish are eating all of the food you put in the tank.

    • 3

      Ensure your aquarium's temperature is between 68 and 86 degrees Fahrenheit to encourage nitrifying bacteria growth. This organism consumes ammonia and converts it into a less-toxic compound. This temperature range is ideal because the metabolism of nitrifying bacteria greatly decreases at temperatures below 50 degrees, while temperatures above 95 degrees are threatening to the fish. Make sure the temperature is appropriate to the fish in your tank as well as to the bacteria.

    • 4

      Oxygenate your fish aquarium by creating surface agitation. This can be done with a hang-on-back filter or a bubbling air stone. Having enough oxygen in the tank will support nitrifying bacteria and help them perform their role in breaking down ammonia.

    • 5

      Avoid using medication in your aquarium. Many fish medications are antibiotics, which will kill bacteria in your tank, including the nitrifying bacteria.